diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index e3755df63..9db266cb6 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -1725,6 +1725,12 @@ static void classicScanSector(int16_t startsectnum)
             if (dmulscale32(p1.x, p2.y, -p2.x, p1.y) >= 0)
                 goto skipitaddwall;
 
+            if (numscans >= MAXWALLSB-1)
+            {
+                OSD_Printf("!!numscans\n");
+                return;
+            }
+
             if (get_screen_coords(p1, p2, &xb1[numscans], &yb1[numscans], &xb2[numscans], &yb2[numscans]))
             {
                 // Made it all the way!
diff --git a/source/build/src/polymost.cpp b/source/build/src/polymost.cpp
index f7ab1bd64..faa166af9 100644
--- a/source/build/src/polymost.cpp
+++ b/source/build/src/polymost.cpp
@@ -4963,6 +4963,12 @@ void polymost_scansector(int32_t sectnum)
             p2 = { (((fp2.y * fcosglobalang) - (fp2.x * fsinglobalang)) * (1.0/64.0)),
                    (((fp2.x * cosviewingrangeglobalang) + (fp2.y * sinviewingrangeglobalang)) * (1.0/64.0)) };
 
+            if (numscans >= MAXWALLSB-1)
+            {
+                OSD_Printf("!!numscans\n");
+                return;
+            }
+
             //if wall is facing you...
             if ((p1.y >= SCISDIST || p2.y >= SCISDIST) && (nexttoward(p1.x*p2.y, p2.x*p1.y) < p2.x*p1.y))
             {